"Use Full CLNP or Null Internet?"

    A CLNS OSI Transport template can specify use of Internet/ES-IS
    routing protocols or Null Internet routing protocol. The Null
    Internet protocol only operates over LAN Routing circuits.

    A CLNS OSI Transport template for use with Internet/ES-IS routing
    protocols may use any Routing circuits configured; the Routing
    module will determine the most suitable circuit to use. A
    CLNS OSI Transport template for use with Null Internet routing
    protocol can only use one Routing circuit; the Routing circuit is
    selected based on its inactive area address.